If statement inside Struct Declaration C++

Question

I have a doubt regarding structs and if statements in C++

For the sake of simplicity, I have created a sample code to explain my intention

int var = 10

struct example{
    int a;
    int b;
    if(var > 8){
        int c;
    }
};

I have a codebase which uses similar kind of code as above. Commenting out the if portion does not give any errors. My question is

• Could if statements be put in struct declarations?
• If not, what is the possible remedy for this, since if statment is mandatory.

Note: I cannot use #if,#else directives nor std::optional or other standard libraries to mitigate this, so please help me find another solution.

Answer 1

No you can't use if statement inside your struct or class definition. Instead, for condition declaration, you can use #if directive.

#define var 10
struct example {
    int a;
    int b;
    #if var > 8
        int c;
    #endif
}

This will work.

'#if' is a compiler directive (pre-processor directive). if statement on the other hand is runtime statement.

Other than this there is no other way!

Answer 2

int main()
{
    int var = 10;
     if(var>10){
                struct example{
                int a;
                int b;
                int c;

             };
            }else {
                    struct example{
                    int a;
                    int b;

                  };

                }
      cout<<"Hello World";

       return 0;
}

There are multiple ways to address your problem one way of achieving is shown.

We cannot add if Statement in the Structure.